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Biomedical subjects

J Scher

Publications and source records attributed to J Scher.

At least 19 recordsLinked to original sources
PubMed2006

Surface composition of dairy powders observed by X-ray photoelectron spectroscopy and effects on their rehydration properties.

The surface composition of three dairy powders was investigated by X-ray photoelectron spectroscopy. These spray-dried casein powders were more or less enriched in hygroscopic material (lactose and/or minerals). The principal limitation of these high protein content powders is their poor rehydration ability. Consequently, information about surface composition is required in order to get a better understanding of rehydration behaviour (i.e. wetting time and time of rehydration). The obtained results indicate that the surface of the three powders was dominated by proteins. Lactose and minerals are marginal compounds at the surface whereas the surface coverage of fat was over represented. A correlation between the lactose surface content and the wetting time of the powders was found, but no relationship with the surface fat. Moreover, as the surface is partly depleted in minerals and lactose, it is concluded that these compounds are principally located in the bulk of the particle. Therefore this observation could be related with a wetting time of the powders only slightly affected by the addition of hygroscopic material whereas the time of rehydration was strongly improved; powder wetting being more affected by the surface composition whereas powder dispersion being more influenced by the powder bulk composition.

Caseins↗
PubMed2006

Modeling of lactose crystallization and color changes in model infant foods.

Lactose crystallization and color changes in formulas containing beta-lactoglobulin and gelatinized starch were investigated. Model infant formulas were prepared by colyophilization of 3 components (lactose, beta-lactoglobulin, and gelatinized starch). A mixture design was used to choose the percentage of each mixture component. These formulas were stored for 3 mo at different relative humidities (RH), ranging from approximately 0 to 94.6%, to study the lactose crystallization and color changes. Crystallization kinetics was studied by gravimetric methods, and lactose state (crystalline vs. amorphous) was verified before and after storage by differential scanning calorimetry. Before storage, lyophilized lactose was amorphous, but during storage it crystallized, depending on the RH. The lactose crystallization RH depended on the quantity of beta-lactoglobulin and gelatinized starch, and by increasing these quantities, the crystallization RH increased. For some formulas, the crystallization RH was noted at 3 different RH during storage. The first was noted after 1 d of storage and the second and third were observed later on, showing that crystallization is a time-dependent phenomenon. Nonenzymatic browning was studied in model infant formulas by yellow color changes of samples at 11.3, 43.2, 54.5, and 75.4% RH. In this study, 7 mathematical models were proposed to predict the moisture sorption properties and color changes at different RH, and the models were validated by experimental results.

Adsorption↗
PubMed2005

Use of a turbidity sensor to characterize micellar casein powder rehydration: influence of some technological effects.

A simplified method to study rehydration of dairy powders was developed for native phosphocaseinate powder. The method involved dispersing powder in a stirred vessel equipped with a turbidity sensor under standardized conditions. The changes of turbidity occurring during powder rehydration highlighted several stages. These stages include particles wetting, and then swelling as the water penetrates into the powder bed, followed by a slow dispersion of the particles. With this tool, some technological effects on powder rehydration were analyzed. Ultrafiltrate incorporation to the casein concentrate before spray drying was found to greatly improve the rehydration, whereas mixing ultrafiltrate powder with casein powder after spray drying did not change the rehydration properties. The effect of granulation on powder rehydration stages was also investigated.

Caseins↗
PubMed2004

Lactose/beta-lactoglobulin interaction during storage of model whey powders.

The objective of this study was to evaluate the presence or absence of interaction between lactose and beta-lactoglobulin during storage of model whey powders at different water activities (a(w)). Model whey powders were prepared by colyophilization of lactose with increasing quantities of beta-lactoglobulin. These colyophilized beta-lactoglobulin:lactose powders, assigned as BL powders, were stored from 0.11 to 0.95 a(w). The water sorption behavior of BL powders was studied gravimetrically, and the state of lactose was investigated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Before storage, BL powders were amorphous. After storage, a loss of water was observed on moisture sorption isotherms of BL powders. It was related to the formation of lactose crystals, detected by DSC and SEM analysis, and to the structural collapse of the powders. Water loss due to lactose crystallization was shifted to higher a(w) with increasing beta-lactoglobulin content in BL powders. Moreover, kinetics of moisture sorption demonstrated that beta-lactoglobulin was also responsible for a slower crystallization process in BL powders. Then, the water sorption behavior of BL powders was very different from the behavior of the 2 compounds mixed after separate lyophilization. All these results pointed out interaction between lactose and beta-lactoglobulin, which appeared during lyophilization and still occurred during storage. This lactose/beta-lactoglobulin interaction stabilized model whey powders against lactose crystallization.

Adsorption↗
PubMed2003

Gene regulation of melatonin and dopamine receptors during eye development.

To gain insight into the role of melatonin and dopamine in retinal development, gene expression of two melatonin receptors, MT1 and MT2, as well as five dopamine receptors, D1, D2, D3, D4 and D5, in the rat eye was analyzed by reverse transcription-polymerase chain reaction across various developmental stages. MT1 transcript levels reached maximum levels at embryonic day (E) 16 and then decreased gradually until reaching adult levels by postnatal day (P) 14. MT2 transcript levels similarly peaked at E16, but then decreased dramatically until birth to its lowest levels, which were maintained throughout the postnatal period. Thus, gene expression of both the MT1 and MT2 receptors showed a striking inverse correlation with maturation of the eye. In contrast to melatonin receptors, gene expression of all dopamine receptor subtypes, except for D3, showed only an increase as development proceeds with highest levels in adulthood. The D3 message was not detected throughout the developmental period examined. Gene expression of D1-like receptors, D1 and D5, showed a substantial increase to adult levels during the fetal period at E16 and E20, respectively. Transcript levels of D2-like receptors, D2 and D4, on the other hand, were not detected before birth but increased significantly to adult levels by P7 and P14, respectively. The present findings suggest the presence of unique developmental mechanisms by which transcription of various G protein-coupled receptors are regulated in the eye.

Aging↗
PubMed2000

Clinical experience with IVIg Rx in patients with prior failed IVF pregnancies: report of 30 consecutive patients.

PROBLEM: This study reviews one practitioner's experience with intravenous immunoglobulin (IVIg) therapy in the in-vitro fertilization (IVF) cycles of 30 patients with previous IVF failures. METHOD OF STUDY: Thirty patients had undergone 82 prior assisted reproductive technology (ART) cycles (mean 3.9 +/- 2 failed ART cycles, median 3.0, range 1-8) yielding one term birth, one loss at 22.5 weeks, and five chemical pregnancies. These patients underwent comprehensive clinical and laboratory evaluation, including immunologic workup, and were accepted for IVIg therapy in their next IVF cycle. RESULTS: A total of 40 cycles were treated. Twenty-four (60%) of the IVIg-treated IVF cycles showed a positive human chorionic gonadotropin test. Comparing the IVIg cycles to the untreated ART cycles, there were no differences in the number of embryos transferred, fertilized embryos, or eggs. Eighty-six percent of the cases with confirmed implantation delivered; there was one chemical pregnancy, one 20-week spontaneous fetal death, and one trisomy. Five (24%) of the 21 pregnant patients delivered at 30-36 weeks. The remaining 13 delivered at term. Only three (11%) had no positive immune test. CONCLUSION: In what may be a selected population of IVF patients (with high incidence of abnormal immune testing), early IVIg therapy may be associated with the improved success of IVF, and the high rate of live birth.

Adult↗
PubMed1997

Pregnancy loss in the antiphospholipid-antibody syndrome--a possible thrombogenic mechanism.

BACKGROUND: The mechanisms of vascular thrombosis and pregnancy loss in the antiphospholipid-antibody syndrome are unknown. Levels of annexin V, a phospholipid-binding protein with potent anticoagulant activity, are markedly reduced on placental villi from women with this syndrome. Hypercoagulability in such women may therefore be due to the reduction of surface-bound annexin V by antiphospholipid antibodies. To test this idea, we studied how antiphospholipid antibodies affect levels of annexin V on cultured trophoblasts and human umbilical-vein endothelial cells and how they affect the procoagulant activity of these cells. METHODS: We isolated IgG fractions from three patients with the antiphospholipid-antibody syndrome and from normal controls. These antibodies were incubated with cultured BeWo cells (a placental-trophoblast cell line), primary cultured trophoblasts, and human umbilical-vein endothelial cells. Annexin V on the cell surfaces was measured by an enzyme-linked immunosorbent assay. The coagulation times of plasma overlaid on the cells were also determined. RESULTS: Trophoblasts and endothelial cells exposed to antiphospholipid-antibody IgG as compared with control IgG had reduced levels of annexin V (trophoblasts, 0.37 +/- 0.02 vs. 0.85 +/- 0.12 ng per well, P=0.02; endothelial cells, 1.6 +/- 0.04 vs. 2.1 +/- 0.05 ng per well, P=0.001). Also, trophoblasts and endothelial cells exposed to antiphospholipid-antibody IgG had faster mean (+/- SE) plasma coagulation times than cells exposed to control IgG (trophoblasts, 8.7 +/- 2.0 vs. 21.3 +/- 2.9 minutes, P=0.02; endothelial cells, 9.8 +/- 0.8 vs. 14.2 +/- 1.2 minutes, P=0.04). CONCLUSIONS: Antiphospholipid antibodies reduce the levels of annexin V and accelerate the coagulation of plasma on cultured trophoblasts and endothelial cells. The reduction of annexin V levels on vascular cells may be an important mechanism of thrombosis and pregnancy loss in the antiphospholipid-antibody syndrome.

Abortion, Spontaneous↗
PubMed1997

Prothrombin activation fragment (F1.2) is increased in pregnant patients with antiphospholipid antibodies.

Recurrent fetal wastage has been attributed to thrombosis in the antiphospholipid antibody syndrome (APAS); however, this has not been proven. Assays of coagulation activation fragments which may provide evidence for a role for thrombosis, have not been previously reported in this setting. We therefore investigated whether F1.2 levels are altered in APAS pregnancies. F1.2 levels were performed on plasmas obtained from fifty-four APA patients with a history of persistent elevation of antiphospholipid antibodies and recurrent abortion who were studied during eighty-three consecutive visits. Results from these patients were compared to a control group of thirty-two healthy pregnant females. F1.2 levels were significantly higher in APAS patients than controls in the second trimester (6.5 nM +/- 4.3 nM vs. 1.2 nM +/- 0.9 nM, p < 0.0001), and in the third trimester of pregnancy (8.6 nM +/- 2.5 nM vs. 3.7 nM +/- 2.0 nM, p < 0.0001). The F1.2 levels in the APA group returned to baseline soon after delivery. No correlation was observed between F1.2 and APA values. This study shows that pregnant patients with a history of recurrent abortions and APA have significantly increased activation of prothrombin compared to healthy pregnant females. These data indicate that the potential value of activations peptide assays such as F1.2 in this setting should be tested in prospective clinical trials.

Adult↗
PubMed1997

Antiphospholipid immunoglobulin G antibodies reduce annexin-V levels on syncytiotrophoblast apical membranes and in culture media of placental villi.

OBJECTIVES: The mechanism by which antiphospholipid antibodies are associated with pregnancy loss and thromboembolism has not been established. We previously showed that annexin-V, a phospholipid-binding protein with potent anticoagulant activity, is present on the apical membranes of the syncytiotrophoblasts that line placental villi and that this protein is reduced, by immunohistochemistry, on placentas of patients with antiphospholipid antibodies. We therefore investigated whether annexin-V in apical membranes of placental villi is quantitatively reduced by antiphospholipid antibody immunoglobulin G. STUDY DESIGN: Placentas were obtained from an index patient with antiphospholipid syndrome with intrauterine growth restriction and from a patient with an uncomplicated pregnancy who were both delivered by cesarean section. Apical villous membranes were isolated and annexin-V levels were measured by enzyme-linked immunosorbent assay. We then studied the effects of antiphospholipid immunoglobulin G on placental villous apical annexin-V in vitro. Antiphospholipid immunoglobulin G was isolated from the sera of five different patients with antiphospholipid antibody syndrome along with five paired control immunoglobulin Gs. Short-term cultures were established from normal placental villi and were exposed to the antibodies, after which isolated apical membranes and culture media were immunoassayed for annexin-V levels. RESULTS: Measurements of apical membrane-associated annexin-V from the antiphospholipid placenta showed significantly less apical membrane-associated annexin-V than did the normal placenta (mean +/- SEM: 4.9 +/- 0.4 micrograms/gm villi for antiphospholipid placenta vs 10.2 +/- 0.6 micrograms/gm villi for control, p < 0.001, n = 4). Exposure of placental villous cultures to five different antiphospholipid immunoglobulin Gs for 24 hours resulted in significant reduction of the levels of apical membrane annexin-V (mean +/- SEM: 3.9 +/- 0.3 micrograms/gm villi) compared with paired controls (5.1 +/- 0.3 micrograms/gm villi, p = 0.02). Villi incubated with the different antiphospholipid immunoglobulin Gs had significantly less annexin-V in conditioned media (mean +/- SEM: 45.1 +/- 4.9 ng/gm villi) compared with the paired normal immunoglobulin G control levels (72.6 +/- 11.4 ng/gm villi, p = 0.03). CONCLUSIONS: Antiphospholipid immunoglobulin G reduces the levels of syncytiotrophoblast apical membrane-associated annexin-V in placental villi and the release of annexin-V into surrounding media. Reduction of this anticoagulant protein at the maternal-fetal interface may account for the pregnancy loss observed in patients with antiphospholipid syndrome. Short-term culture of placental villi may offer an in vitro model to further study the mechanism of this effect of antiphospholipid antibodies.

Adult↗
PubMed1996

Correlation between karyotype and ultrasound findings in patients with failed early pregnancy.

The aim of this retrospetive study was to identify any consistent patterns between ultrasound findings in failed pregnancies and either normal or abnormal karyotypes. The study involved 102 women in whom the diagnosis of early pregnancy failure was made sonographically. The criteria for a failed pregnancy were: a gestational sac with a mean diameter of > 12 mm without a yolk sac; a yolk sac of > 6 mm mean diameter with or without abnormal morphology that ultimately failed to develop an embryonic structure; and an embryo with a crown--rump length (CRL) of > 5 mm without cardiac activity, or the loss of previously identified cardiac activity. All patients underwent elective dilatation and curettage (D & C) and products of conception were sent for karyotyping. Forty-four pregnancies (43%) had abnormal karyotypes. Of these, 33 (75%) were trisomies. The other 11 included four triploidies, one tetraploidy, two with monosomy X, and four others (unbalanced complement, isochromosome, terminal deletion and translocation). Fifty-eight pregnancies (57%) had normal karyotypes, of which 52 were 46,XX and six were 46,XY. The furthest sonographic anatomic landmark achieved did not differ with respect to karyotypic findings. An abnormal yolk sac was found in 10/58 cases (17.2%) with normal karyotypes and 8/44 cases (18.2%) with abnormal karyotypes. There were eight cases of trisomy 16, of which only two manifested an embryonic structure, but neither of which had cardiac activity; the largest was 4 mm. There were four cases of trisomy 22, of which three developed embryos with a CRL of > 10 mm with cardiac activity (11, 11 and 18 mm, respectively). In three cases of mosaicism, embryos developed cardiac activity, and were 9, 19 and 16 mm. Two cases of monosomy X had embryos of 14 and 24 mm. Only one out of five cases with multiple trisomies developed to a point at which any embryonic structure was identifiable on ultrasound examination. The ultrasound appearance of early pregnancy failure in terms of furthest anatomic landmark reached was not significantly different in cases with normal or abnormal karyotype. An abnormally enlarged yolk sac, presumably secondary to hydropic change, is a non-specific finding of failed pregnancy, and did not correlate with karyotypic abnormality (trisomy 22, mosaic, monosomy X) seem to develop further prior to embryonic demise than those with certain others (trisomy 16, multiple trisomies and unusual other variants.

Abortion, Spontaneous↗
PubMed1994

Reduction of annexin-V (placental anticoagulant protein-I) on placental villi of women with antiphospholipid antibodies and recurrent spontaneous abortion.

OBJECTIVE: The mechanism by which antiphospholipid antibodies are associated with pregnancy loss and thromboembolic conditions has yet to be elucidated. Annexin-V, an anticoagulant phospholipid-binding protein, is normally present in syncytiotrophoblasts lining the placental villi, where it may play a role in the maintenance of intervillous blood fluidity. We therefore investigated the distribution of annexin-V in placentas of patients with antiphospholipid antibodies in situ and then used short-term villous cultures to study the direct effect of antiphospholipid antibodies on the immunolocation of annexin-V. STUDY DESIGN: We performed a blinded study by means of computerized morphometric analysis of placental tissues that were stained for annexin-V with affinity-purified polyclonal antibody in an avidin-biotin peroxidase system. The distribution of villous surface annexin-V on cross sections of placentas of patients with antiphospholipid antibodies was compared with that of placentas from patients with uncomplicated pregnancies, elective abortions, and pregnancy losses not associated with antiphospholipid antibodies (n = 8 for each group). We quantitated villous surface annexin-V in cultured placental villi that were incubated with antiphospholipid antibodies immunoglobulin G compared with normal immunoglobulin G and measured annexin-V levels by enzyme-linked immunosorbent assay in conditioned media and in the villi. RESULTS: The mean villous surface annexin-V of the group with antiphospholipid antibodies was 26.2% +/- 17% (SD) versus 93.9% +/- 5.7% in the normal control group (p < 0.0001). Villi from patients undergoing elective abortions and with pregnancy losses that were not attributed to antiphospholipid antibodies also showed higher mean villous surface annexin-V levels (86.9% +/- 10.6% and 83.5% +/- 11.3%, respectively, p < 0.0001). Organ culture of normal placental villi with affinity-purified immunoglobulin G from patients with antiphospholipid antibodies showed a dose-dependent decrease of villous surface annexin-V over a concentration range of 1.5 micrograms/ml to 1.5 mg/ml. Annexin-V concentrations in conditioned media were significantly lower in the presence of antiphospholipid antibodies immunoglobulin G compared with normal immunoglobulin G (49.4 +/- 8.9 ng/gm wet weight vs 57.2 +/- 11.5 ng/gm, respectively, p < 0.05). In contrast, the mean level of annexin-V in placental villi incubated with antiphospholipid antibodies immunoglobulin G was greater than in villi incubated with normal immunoglobulin G, 1328 +/- 130 ng/gm wet weight versus 1183 +/- 165 ng/gm (p < 0.02). CONCLUSIONS: Patients with antiphospholipid antibodies and a history of previous pregnancy losses have a significant reduction in annexin-V immunostaining on placental villous surfaces, and antiphospholipid antibodies immunoglobulin G can directly decrease levels of villous surface annexin-V on cultured placental villi. Assays of annexin-V in the conditioned media and cell pellets of cultured placental villi suggest that the mechanism for antiphospholipid antibodies-mediated reduced annexin-V surface staining is an inhibition of annexin-V transport to the villous surface rather than displacement by antiphospholipid antibodies from the surface. This antiphospholipid antibodies-induced deficiency of placental surface annexin-V may contribute to the placental thrombosis observed in these patients.

Abortion, Habitual↗
PubMed1982

The incidence and outcome of asymptomatic herpes simplex genitalis in an obstetric population.

In a prospective study of an obstetric population, 28 of 488 (4%) routine asymptomatic patients had positive cultures for herpes simplex virus from their genital tract. Cesarean section was carried out if the virus was present in the genital tract at the time of delivery. In one instance, a culture which had reverted to negative became positive again. No cases of neonatal herpes were reported in the time of the study. As yet, the infectivity of these subclinical cases is unclear, and the incidence of neonatal herpes is not as high as would be expected from the study. Further studies need to be carried out to evaluate the exact risk of the asymptomatic herpesvirus shedder to the infant at birth.

Adult↗
PubMed1981

A new abortion technique: intravaginal and intramuscular prostaglandin.

The 15-methyl analog of prostaglandin F2 alpha (15-ME-PGF2 alpha), administered in a 3-mg dose via a single vaginal suppository and supplemented at 24 hours by intramuscular injection(s) of 250 micrograms, successfully induced abortion in 80 of 81 patients in the midtrimester of pregnancy. The mean abortion time was 19.6 hours. Two thirds of the patients aborted after treatment with the suppository alone in a mean time of 14.6 hours; the remaining 27 patients required intramuscular injections of 15-ME-PGF2 alpha to effect expulsion of the products of conception. Twenty-six of these 27 patients subsequently aborted in a mean total abortion time of 29.6 hours. Fifty-eight patients aborted within 24 hours of the initial prostaglandin administration, and 78 aborted by 36 hours. Parity and length of gestation did not significantly affect abortion time in this series, although the mean abortion time for parous patients and patients with gestations earlier than 17 weeks tended to be somewhat shorter than that of nulliparous patients and those with more advanced gestations. The placenta was spontaneously expelled in the majority of patients. Abortion was incomplete in 3 patients and required curettage. Uterine activity, as measured via an intraamniotic catheter in 6 patients, developed very gradually with the suppository, peaking at 3 hours after insertion, and was characterized by regular contractions with low intrauterine baseline tonus. The gastrointestinal side effects that occurred in 59% of patients who received the suppository were also most frequently observed at 3 hours after administration. In contrast the gastrointestinal disturbances elicited by intramuscular injections of the analog immediately followed the administration.

Abortion, Induced↗
PubMed1980

A comparison between vaginal prostaglandin E2 suppositories and intrauterine extra-amniotic prostaglandins in the management of fetal death in utero.

This retrospective study was undertaken to compare the efficacy, side effects, and complications of prostaglandin E2 (PGE2) given as a vaginal suppository with those of PGE2 administered via the intrauterine extra-amniotic route to induce labor after fetal death. The induction-to-delivery intervals were comparable, with 9.2 +/- 3.94 hours and 8.6 +/-4.49 hours, respectively. However, the mean total amount of PGE2 administered was much less via the intrauterine extra-amniotic route (1.8 milligrams) than by the vaginal suppository (45.2 mg). There was a 100% success rate in the patients treated by the intrauterine extra-amniotic route, but only a 91.3% success rate in those patients treated via the vaginal route. The side effects (vomiting, diarrhea, fever) and the complications (incomplete abortion, uterine rupture, oxytocin augmentation) occurred more frequently with the use of PGE2 as a vaginal suppository. The vaginal route of administration of PGE2 is somewhat more convenient, but the intrauterine extra-amniotic route may offer a higher degree of efficacy and safety with fewer side effects in the management of fetal death in utero.

Abortion, Therapeutic↗
PubMed1980

Post-conceptional induction of menses with a single vaginal suppository of (15S)-15-methyl prostaglandin F2 alpha methyl ester.

The induction of post-conceptional menses needs a technically simple method which would avoid instrumentation of the uterus. One possible method investigated in this study is the abortifacient effect of a single dose long-acting vaginal suppository containing 3.0 mg of (15S)-15-methyl prostaglandin F2 alpha methyl ester. Pregnancy was terminated successfully in 13 of the 14 subjects. Two successful patients required curettage for prolonged bleeding and retained products of conception. Prolonged vaginal bleeding and the uncertainty of endpoints with particular reference to human chorionic gonadotropin (HCG) constitute the major problem with this non-invasive method, and are discussed in the light of the data obtained.

Abortion, Induced↗
PubMed1976

Comparison of oral prostaglandin E2 and intravenous oxytocin for induction of labour.

A carefully controlled, prospective study was undertaken in 100 patients to compare orally administered prostaglandin E2 capsules with intravenous oxytocin in the induction of labour at term. Orally administered prostaglandin E2 induced labour in slightly more patients than did intravenous oxytocin (48 out of 50 v. 45 out of 50) and a larger trail is in progress to evaluate this observation further. Mild gastro-intestinal symptoms occurred in 28% of the patients when oral prostaglandin was given. However, the oral route is more convenient and more comfortable for the patient and the administration requires less adjustment by the nursing staff.

Administration, Oral↗